Footage has emerged of the moment the Duchess of Cambridge appeared to let slip the sex of her unborn baby – and it has done little to dampen speculation that she is expecting a girl.

Despite official denials that the duchess had given the game away, the video of the blushing mother-to-be seems to validate claims that she began to say the word ‘daughter’.

The Mail told yesterday how the duchess made her intriguing remark during a walkabout in Grimsby on Tuesday, when she was handed a teddy bear by wellwisher Diana Burton.

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Hint: The Duchess of Cambridge said 'Is this for our d...' as she was handed a teddy bear by a well-wisher

Smile through it: Kate seems to try to gloss over her first sentence by continuing to thank the woman

Out of the bag? Kate is questioned by members of the crowd as she continues to walk along the line of well-wishers. Sandra Cook asks her: 'Did you say my daughter?'

She was overheard by members of the 2,000-strong crowd saying: ‘Is this for our d . . . ’ before stopping abruptly. Bookmaker William Hill said it was forced to suspend betting on the baby’s sex at 10pm on Tuesday as the story got out and punters rushed to put their money on the arrival of a princess.

Rival Ladbrokes is still open for business – although odds on a girl have plummeted from 4/5 to 1/2, while odds of 6/4 are being offered to those who think the baby will be a boy.

Now footage of the incident discovered by Sky News appears to validate the witness reports.

Slip up? Kate appeared slightly flustered when she was questioned but immediately regained her composure

Secret's out? Kate wagged her finger and appeared to blush as she denied she was about to say 'daughter'

Blushes: Kate said she and Prince William do not know the sex of the baby before looking at the ground

Mrs Cook neither asked for nor received payment for talking about her encounter with the Duchess and said: 'I very much hope that I haven't upset her. I was so thrilled to have met her and just recalled what I heard.

'She was absolutely lovely and I never expected for a second that what I said would cause so much debate.'

St James’s Palace has declined to comment, although well-placed sources insist Kate and her husband William have not yet found out their baby’s sex.

Diana Burton, 41, who gave Kate the
teddy, was too shell-shocked to recall the conversation. But Mrs Cook,
who works in a local charity shop and lives in Grimsby, was adamant
about what she heard.

‘I only hope that she doesn’t now give birth to a boy or I’m going to look pretty stupid,’ she said.

THE WORDS THAT HAVE CAUSED A STIR AROUND THE WORLD

Duchess of Cambridge, as she is handed a teddy bear: 'Oh is this for our d.... [brief pause]

Although it is still one of the
largest centres for fish processing in Britain, Grimsby has been in
decline since the 1950s and youth unemployment is among the highest in
the country.

At a later visit to the Humberside
Fire and Rescue Service, Kate was shown the fleet of fire engines.

At the end of the visit, Kate was given a bouquet by 11-year-old Evie Oxley, whose
fireman father is being treated for cancer and whose mother was recently
given the all-clear from breast cancer.

'She
said I had been very brave, with my dad being poorly,' said Evie. 'It's
tough at times but you have to get over it sometimes and just be brave.
If you're not brave then the person that's ill is not going to be brave
either.'

Dressed in a Hobbs coat and a Great Plains dress, the Duchess made an unplanned stop to speak to ten adults and children who are patients at the nearby St Andrew's Hospice.

You shouldn't have! Five months pregnant Kate is delighted to accept the adorable gift for her baby

A teddy for Kate: Diana Burton, 41, pictured waiting patiently with the crowd for the arrival of the Duchess

Patient Claire Moss-Smith, 86, told the Duchess: ‘I’m waiting for you to be Queen.’

Kate replied with a smile: ‘You might be waiting for a long time.’

Kate was on
what the palace call a 'royal away day' in north east Lincolnshire - a
chance to cram in as many engagements as possible in a particular area
of the country.

As well as
visiting the fishing museum, which commemorated the town's trawling
industry, and the fire station, the Duchess also unveiled a plaque at
the Havelock Academy.

Two princesses: Earlier on Kate was given gifts of flowers by children at the Peaks Lane Fire Station

Patriotic: Schoolchildren held up Union Flags as the Duchess of Cambridge arrived at the Havelock Academy